Chain tensioning devices and drive assemblies for mining

ABSTRACT

A drive assembly for use with mining apparatus such as conveyors or coal ploughs includes a chain tensioning device which is in the form of a self-contained unit or cartridge.

Unite States Patent Gibson et a1.

[ CHAIN TENSIONING DEVICES AND DRIVE ASSEMBLIES FOR MINING Inventors: John Gibson, 61 Welbury Grove,

Newton Avcliffe; James Nelson, 47 Briar Ln., Shiney Row, Houghton 1e Spring, both of England [22] Filed: June 26, 1972 App1.No.: 266.309

Foreign Application Priority Data June 30, 1971 Great Britain 30641/71 [52] US. Cl. 74/661, 74/665 B Int. Cl. Fl6h 37/06 [58] Field of Search 74/661, 665 B Primary Exan11ner-Sumue1 Scott Assistant Examiner-J. Recp Attorney, Agent, or Firm-Thompson, Birch, Gauthier & Samuels [57] ABSTRACT A drive assembly for use with mining apparatus such as conveyors or coal ploughs includes a chain tensioning device which is in the form of a. self-contained unit or cartridge.

8 Claims, 5 Drawing Figures PATENTEDFEB 41% 3.863522 SHEET 10F 5 Fig .1

PATEHTEDFEB 41% 3.863522 SHEET 2 BF 5 PATENTEU FEB 41975 SHEET 3 BF 5 PATENTEU FEB 415175 SHEET 5 BF 5 CIIAIN TENSIONING DEVICES AND DRIVE ASSEMBLIES FOR MINING BACKGROUND OF THE INVENTION A drive assembly or station for mining apparatus such as a conveyor or a coal plough is required to drive one or more chains by way of a rotary drum. It is often desired for the drive assembly to drive the drum at a low speed very much below the normal operating speed so as to slacken or tension the previously locked chain or chains during installation or repair work for example. To this end, a drive assembly is known which employs an additional drive motor especially for driving the drum at this low speed.

A standard form of drive assembly has main gearing in a housing which is connected to the machine frame of a conveyor, and is driven from an electric motor through a fluid coupling. In the case of the drive assembly for a plough, a safety device in the form of a shear pin drum is often provided on the side of the gearbox remote from the conveyor and has shear pins which shear if the chain load becomes excessive.

When auxiliary gearing is required to drive the chain drum at a low speed, the construction described above must be extensively modified and two different types of drive assembly manufactured, one with and one with out auxiliary gearing. In consequence both the manufacturer and the user have to incur the expense of bolding extra stocks. Also, where the user needs to change from an assembly without auxiliary gearing to one with such gearing, or vice-versa, difficulties are encountered since these tasks have to be performed in dirty and badly lit conditions in restricted spaces underground.

SUMMARY OF THE INVENTION Broadly stated, the present invention provides a drive assembly which comprises a rotatable member which is driven from a main drive means through a transmission which includes main gearing and a toothed disc carried on a shaft; and auxiliary gearing providing a reduction ratio and including a pinion which is movable under the action of a shifting device to selectively engage the toothed disc to thereby drive the rotatable member via the auxiliary gearing. The transmission also includes a fluid coupling device or a flexible rubber type coupling which is disposed in a housing into which extends the shaft which carries the toothed disc. The auxiliary gearing is removable from the assembly and, in a preferred embodiment, the auxiliary gearing, the toothed disc and its shaft constitute a selfcontained detachable unit. The rotatable member may be a drum used to drive the chain or chains of a mining apparatus and the auxiliary gearing can be used to drive the rotatable member at a low tensioning or slackening speed in chain adjustment operations.

Auxiliary drive means which maybe a fluid driven motor is preferably provided, the auxiliary drive means being operable as an alternative to the main drive means to drive the rotatable member via the auxiliary gearing. The auxiliary drive means, auxiliary gearing and the toothed disc thus constitute a chain-tensioning device which is independent of the remaining parts of the drive station. A drive assembly made in accordance with the invention is readily adaptable so that the chain tensioning device can be removed if not required. The drive assembly can thus be more economical both from the point of view of the manufacturer and the user.

If a drive assembly without a chain tensioning device has to be converted to one with such a device, or vice versa, in an underground site, the time necessary to carry out these operations is considerably shortened by employing the drive assembly of this invention, and these operations can be carried out by untrained personnel without the adoption of special precautionary measures.

According to an optional feature of the invention the main gearing of the drive assemblly may consist of primary and secondary gearing, the primary gearing being connected to a shear pin drum which is disposed substantially coaxially of and facing said further housing. The drive assembly made in accordance with the invention enables standardized primary and secondary gearings to be employed. This construction also ensures that the chain tensioning device will not impede the access to the drive assembly and associated equipment especially when shear pins are to be changed. Also a miner can operate both the chain tensioning device and a shear pin drum when the latter is provided from one working position and with complete safety.

The chain tensioning device may be in the form of a self-contained unit or cartridge adapted to be interposed in the drive system, between, for example, the fluid coupling of the main drive motor and the gearbox. The device may include a main shaft comprising a stub shaft portion which is inserted into the fluid coupling and a socket portion which receives the gearbox input shaft. By giving the stub shaft portion the same essential characteristics as the gear box input shaft, as regards dimensions and splining, the chain tensioning device may be incorporated easily into the drive systems of existing installations. The fluid circuit of the auxiliary motor may include valve means which locks the motor when the supply of fluid thereto is terminated so as to maintain the chain in tension.

DESCRIPTION OF DRAWINGS FIG. 1 is a diagrammatic view of a mineral mining installation showing part of a face conveyor and drive assemblies for the conveyor and for a plough, each assembly incorporating a chain tensioning device in accordance with the invention,

FIG. 2 is a cross-section through a chain tensioning device showing the general arrangement of the gearing and control mechanism,

FIG. 3 is a section taken on the line ABC of FIG. 2 and showing one type of main shaft construction,

FIG. 4 is a section taken on the line A-B of FIG. 2 but showing a second type of main shaft construction,

FIG. 5 is a schematic diagram illustrating the hydraulic circuit of the device.

DESCRIPTION OF PREFERRED EMBODIMENT Referring to the drawings, FIG. 1 shows in a diagrammatic form those components ofa mineral mining installation relevant to the present invention namely: a

face conveyor A, a plough B, and drive assemblies C and D for the conveyor and plough respectively.

The drive assembly for the conveyor comprises a drum CE which is driven from an electric motor CF through a gearbox CG, a chain tensioning device CH and a fluid coupling CJ. The drive assembly for the plough likewise comprises a drum DE, electric motor DF, gearbox DG equipped with a :shear pin drum DK, chain tensioning device DH and fluid coupling DJ.

Each gearbox houses main and secondary gearing in known manner, the main gearing of gearbox DG driving the shear pin drum. Each of the components CF to CI and DF to D] has flanges whereby the components are bolted together.

When the installation is working, the drum CE is continuously driven so as to circulate a pair of endless chains L which carry the flights of the conveyor, while the drum DE is driven alternately in opposite directions so that an endless chain M draws the plough B back and forth along the face.

When, for example, during repair work it is necessary to tension either the pair of chains L or the chain M, the electric motor in the appropriate drive assembly is halted, the chain M or pair of chains L, as the case may be, locked by a locking device N or respectively, and the appropriate chain tensioning device operated. FIG. 1 shows the situation after both tensioning devices have operated to tension the lower, return runs of the chains so as to produce amounts of slack chain between the drum and the locking devices. With the tensioning devices maintaining the lower runs in tension, this slack chain may be removed.

Referring now to FIGS. 2 and 3, the tensioning device comprises a housing generally indicated at 1. A main shaft assembly 2 is supported in a bearing 19 supported in the front wall of the housing and consists of a stub shaft component 5 and a socket component 6, the former of which projects forwardly of the housing. The shaft components 5, 6 have peripheral flanges 51 and 61 respectively. Bolts 52 secure the flanges together with a gearwheel 3 sandwiched between them. The socket component is internally splined and the stub shaft component externally splined so that the former can receive the splined input shaft of the gearbox and the latter can be inserted into the fluid coupling in the place of the gearbox input shaft. Within the housing at its other end, a driving pinion 7 is secured to the output shaft 71 ofa hydraulic motor 72 bolted to the housing. Anintermediate gearwheel 8 which is rotatable on a shaft 81 in mesh with the pinion 7 is slidable along this shaft into and out of mesh with the gearwheel 3, under the action of a selector fork which engages with the gear-wheel 8 and is made to slide along a rod 151 by an operating mechanism supported by a box 12 bolted to the housing. The operating mechanism comprises a handle 121, spindle 122 and an eccentric pin 123 cooperating with a groove in the body part of the selector fork.

The spindle 122 has a cam surface 124 which causes a microswitch 44 to open when the handle is moved in the sense of engaging the gears 3 and 8. The leads from the microswitch are connected to a connector block 43, as are the leads from an electrical interlock which is operable, on opening of the microswitch, to interrupt the power supply to the electric motor. To enable the tensioning device when assembled to be operated by either hand as is more convenient, the box 12 and the fork operating mechanism can be bolted to either side of the housing, which is provided with two suitable openings and two rods 151, 152, on either of which the selector fork can be supported.

The construction shown in FIGS. 2 and 3 makes use of a rigid connection between the main shaft components. This rigidity of connection renders it difficult to accommodate errors of alignment when assembling the chain tensioning device with the fluid coupling and gearbox and, to overcome this problem, the stub shaft and socket components may be interconnected with a certain degree of play. Referring now to FIG. 4, it will be seen that the main gearwheel 3, in the form of an externally toothed ring, is bolted to the rim of the peripheral flange 51 of the stub shaft component 5. The ring is formed at intervals with bores 31 into which project pins 62 bolted to the flange 61 of the socket component 6. The shanks of the pins are covered with flexible sleeves or washers 63 retained in place by the heads 64 of the pins, whereby the two flanges 51, 61 are coupled by a flexible coupling of the pin type. In this modification, the stub shaft component is necessarily supported by two sets of bearings 19 instead of the single set in the main embodiment.

A hydraulic control circuit is housed in a manifold (FIGS. 1 and 5) the circuit including a control valve 101 enabling the motor 72 to be placed in neutral or to be driven forwards or in reverse and check valves 102 to isolate and lock the motor 72 when the valve 101 is placed in neutral. A pressure gauge 103 allows the pressure in the system (and hence the chain tension) to be observed, and an adjustable relief valve 104 is provided to divert the flow of fluid from the motor when once a desired tension has been achieved.

It will be understood by those skilled in the art that modifications may be made to the apparatus described above within the spirit and scope of the invention. Thus, for example, in the embodiment shown in FIG. 3, it is not necessary for the gearwheel 3 to be sandwiched between the flanges 51, 61. Instead, these flanges can be bolted directly to each other and the gearwheel 3 fixed to the side of the flange 61.

In some applications it may be desirable for the drive assembly to extend parallel to the conveyor and in this, or in others, alternative hydraulic circuits may be found to be preferable. The sequence of operations for the apparatus described with reference to the drawings may be as follows:

I. The selector handle 121 is operated to engage gear. To prevent the electric motor CF or DF being switched on when the hydraulic drive is engaged, initial movement of the selector handle actuates microswitch 44 which activates the electrical interlock to interrupt the power supply.

2. The chain locking device N or O is engaged.

3. The directional flow control valve 101 is operated. The hydraulic motor 72 then drives the chain drum CE or DE via the main gearbox CG or DG.

4. When the required chain tension is reached, this being determined by reference to the pressure gauge 103 or by operation of the relief valve 104, the flow control valve 101 is moved to neutral and pressure then held in the system by means of check valves 102. The chain M or pair of chains L can be uncoupled and slack chain removed.

5. The directional flow control valve 101 is operated to reverse the hydraulic motor 72, until the chain locking device N or O is free.

6. The flow control valve 101 is returned to neutral and the chain locking device N or O removed.

7. The selector handle 121 is operated to disengage gear and automatically disengage the electrical interlock on the power supply.

We claim:

1. A chain tensioning device (CH or DH) in the form of a self-contained unit adapted to be interposed and interconnected between two components (e.g. CG and CI) of a drive assembly for a mineral mining installation, one of said components having a stub shaft projecting therefrom and the other of said components having a socket into which said stub shaft is normally seated, said chain tensioning device comprising;

a. a housing (1) having front and rear sides;

b. a main shaft assembly (2) supported for rotation within said housing and interconnecting said two components, said assembly including;

i. a main gear wheel (3) disposed within said housii. a stub shaft part (5) projecting at least partially from the front side of said housing; and

iii. a socket part (6) having a socket opening towards the rear side of said housing;

said main gear wheel, stub shaft part and socket part being engaged so as to be rotatable together;

c. an auxiliary driving motor (72) mounted to said housing (1) and having a drive shaft (71) extending into said housing, said drive shaft (71) being spaced from and parallel to said stub shaft part (5);

d. a pinion (7) carried by said drive shaft (71) within said housing;

e. an intermediate gear wheel (8) disposed within said housing between said main gear wheel (3) and said pinion (7), said intermediate gear wheel having a first axial position engaging and drivably interconnecting both said pinion and said main gear wheel and a second axial position out of engagement with said pinion and said main gear wheel; and

f. means (121-124, for shifting said intermediate gear wheel (8) between the two said positions.

2. The chain tensioning device of claim 1 further having means (62-64) interconnecting said stub shaft part and said socket part, said means permitting play therebetween.

3. The chain tensioning device of claim 1, wherein said driving motor (72) is a hydraulic motor, said device further having a circuit (101-104) for supplying hydraulic fluid to said motor, said circuit including a directional control valve (101) having positions permitting forward and reverse rotation of said motor and a neutral position, and a valve means (102) operable to isolate said motor when said control valve is set in neutral.

4. A chain tensioning device (CH or DH) in the form of a self-contained unit for incorporation and interconnection in the drive assembly of a mining installation, said drive assembly including a main electric drive motor (CF), a circuit for supplying electric current thereto, and a component (CG) to which rotary motion is transmitted from said motor, said component (CG) having a stub shaft projecting therefrom; said chain tensioning device comprising;

a. a housing (1);

b. a main shaft assembly (2) supported for rotation in said housing and connected to said component, said shaft assembly including;

i. a main gear wheel (3); and ii. a socket part (6) dimensioned to releasably receive said stub shaft;

c. an auxiliary driving motor (72) mounted to said housing;

d. a drive shaft (71) extending from said motor (72) into said housing;

e. a pinion (7) carried by said drive shaft (71);

f. an intermediate gear wheel (8) disposed within said housing between said main gear wheel (3) and said pinion (7), said intermediate gear wheel having a first position engaging and drivably interconnecting both said pinion and said main gear wheel and a second position out of engagement with said pinion and said main gear wheel;

g. means (121-124, 15) for shifting said intermediate gear wheel (8) between its two positions; and

h. a switch (44) actuable when said intermediate gear wheel is in its first position to interrupt said circuit supplying current to said main drive motor (CF).

5. The chain tensioning device of claim 4, wherein said means (121-124, 15) for shifting said intermediate gear wheel (8) includes a lever (121) supported upon said housing, and said switch (44) is actuable by said lever.

6. In a drive assembly for a mineral mining installation, the combination ofa main gear box (CG), a resilient coupling unit (CJ), and a chain tensioning device (CH), each of said combination elements having a re spective housing, the three said housings being releasably bolted together with said chain tensioning device being interposed therebetween, one of said gear and coupling housings having a stub shaft projecting therefrom and the other having therein a socket, said chain tensioning device comprising; i

a. a main shaft assembly (2) supported for rotation within its said housing (1) and engaging said stub shaft and said socket, said main shaft assembly comprising;

i. a stub shaft part (5) projecting into said socket;

ii. a socket part (6) within which said stub shaft is seated;

iii. a main gear wheel (3), said stub shaft part, socket part and main gear wheel being engaged so as to be rotatable together and to transmit rotary motion through said main shaft assembly (2) from said main gear box to said resilient coupling unit;

b. an auxiliary drive motor (7.2) mounted to said housing (1) of said chain tensioning device, said motor having a drive shaft (71) extending into said housing;

c. a pinion (7) mounted on said drive shaft (71) within said housing; and

(1. gear means (8) shiftable within said housing (1) into and out of a position in which said pinion (7) and said main gear wheel (3) are drivably interconnected.

7. The drive assembly of claim 6, further having a main electric drive motor (CE) drivably coupled with said main gear box (CG), and electric circuit means for supplying electric current to said main electric drive motor, said chain tensioning device (CH) having a switch (44) operable to interrupt said circuit means when said pinion (7) and said main gear wheel (3) of said chain tensioning device are drivably interconnected.

8. The drive assembly of claim 6, further having means (62-64) interconnecting said stub shaft part and socket part of said chain tensioning device, said means permitting radial misalignment therebetween.

k It l I I 

1. A chain tensioning device (CH or DH) in the form of a selfcontained unit adapted to be interposed and interconnected between two components (e.g. CG and CJ) of a drive assembly for a mineral mining installation, one of said components having a stub shaft projecting therefrom and the other of said components having a socket into which said stub shaft is normally seated, said chain tensioning device comprising; a. a housing (1) having front and rear sides; b. a main shaft assembly (2) supported for rotation within said housing and interconnecting said two components, said assembly including; i. a main gear wheel (3) disposed within said housing; ii. a stub shaft part (5) projecting at least partially from the front side of said housing; and iii. a socket part (6) having a socket opening towards the rear side of said housing; said main gear wheel, stub shaft part and socket part being engaged so as to be rotatable together; c. an auxiliary driving motor (72) mounted to said housing (1) and having a drive shaft (71) extending into said housing, said drive shaft (71) being spaced from and parallel to said stub shaft part (5); d. a pinion (7) carried by said drive shaft (71) within said housing; e. an intermediate gear wheel (8) disposed within said housing between said main gear wheel (3) and said pinion (7), said intermediate gear wheel having a first axial position engaging and drivably interconnecting both said pinion and said main gear wheel and a second axial position out of engagement with said pinion and said main gear wheel; and f. means (121-124, 15) for shifting said intermediate gear wheel (8) between the two said positions.
 2. The chain tensioning device of claim 1 further having means (62-64) interconnecting said stub shaft part and said socket part, said means permitting play therebetween.
 3. The chain tensioning device of claim 1, wherein said driving motor (72) is a hydraulic motor, said device further having a circuit (101-104) for supplying hydraulic fluid to said motor, said circuit including a directional control valve (101) having positions permitting forward and reverse rotation of said motor and a neutral position, and a valve means (102) operable to isolate said motor when said control valve is set in neutral.
 4. A chain tensioning device (CH or DH) in the form of a self-contained unit for incorporation and interconnection in the drive assembly of a mining installation, said drive assembly including a main electric drive motor (CF), a circuit for supplying electric current thereto, and a component (CG) to which rotary motion is transmitted from said motor, said component (CG) having a stub shaft projecting therefrom; said chain tensioning device comprising; a. a housing (1); b. a main shaft assembly (2) supported for rotation in said housing and connected to said component, said shaft assembly including; i. a main gear wheel (3); and ii. a socket part (6) dimensioned to releasably receive said stub shaft; c. an auxiliary driving motor (72) mounted to said housing; d. a drive shaft (71) extending from said motor (72) into said housing; e. a pinion (7) carried by said drive shaft (71); f. an intermediate gear wheel (8) disposed within said housing between said main gear wheel (3) and said pinion (7), said intermediate gear wheel having a first position engaging and drivably interconnecting both said pinion and said main gear wheel and a second position out of engagement with said pinion and said main gear wheel; g. means (121-124, 15) for shifting said intermediate gear wheel (8) between its two positions; and h. a switch (44) actuable when said intermediate gear wheel is in its first position to interrupt said circuit supplying current to said main drive motor (CF).
 5. The chain tensioning device of claim 4, wherein said means (121-124, 15) for shifting said intermediate gear wheel (8) includes a lever (121) supported upon said housing, and said switch (44) is actuable by said lever.
 6. In a drive assembly for a mineral mining installation, the combination of a main gear box (CG), a resilient coupling unit (CJ), and a chain tensioning device (CH), each of said combination elements having a respective housing, the three said housings being releasably bolted together with said chain tensioning device being interposed therebetween, one of said gear and coupling housings having a stub shaft projecting therefrom and the other having therein a socket, said chain tensioning device comprising; a. a main shaft assembly (2) supported for rotation within its said housing (1) and engaging said stub shaft and said socket, said main shaft assembly comprising; i. a stub shaft part (5) projecting into said socket; ii. a socket part (6) within which said stub shaft is seated; iii. a main gear wheel (3), said stub shaft part, socket part and main gear wheel being engaged so as to be rotatable together and to transmit rotary motion through said main shaft assembly (2) from said main gear box to said resilient coupling unit; b. an auxiliary drive motor (72) mounted to said housing (1) of said chain tensioning device, said motor having a drive shaft (71) extending into said housing; c. a pinion (7) mounted on said drive shaft (71) within said housing; and d. gear means (8) shiftable within said housing (1) into and out of a position in which said pinion (7) and said main gear wheel (3) are drivably interconnected.
 7. The drive assembly of claim 6, further having a main electric drive motor (CE) drivably coupled with said main gear box (CG), and electric circuit means for supplying electric current to said main electric driVe motor, said chain tensioning device (CH) having a switch (44) operable to interrupt said circuit means when said pinion (7) and said main gear wheel (3) of said chain tensioning device are drivably interconnected.
 8. The drive assembly of claim 6, further having means (62-64) interconnecting said stub shaft part and socket part of said chain tensioning device, said means permitting radial misalignment therebetween. 